A DFT study on graphene, SiC, BN, and AlN nanosheets as anodes in Na-ion batteries.

A great concern exists about the lifetime, cost, low-temperature performance, and safety of Li-ion batteries. Na-ion batteries (NIB) are an alternative to the Li-ion batteries due to the wide availability of sodium, its low cost, and nontoxicity. Here, we examined the Na and Na+ adsorption on nanosheets of carbon (graphene), AlN, BN, and SiC to explore their potential use as an anode in NIBs. The interaction of atomic Na was found to play the main role in producing different nanosheet cell voltages. Unlike the graphene and SiC nanosheets, the lone pairs on the surface of the AlN and BN nanosheets hinder the Na adsorption and significantly increase the cell voltage. The order of magnitude of the nanosheet cell voltage as an anode in NIBs is as follows: AlN (1.49 V) > BN (1.46 V) > > C (0.69 V) > SiC (0.61 V). The AlN and BN nanosheets may be appropriate compounds for NIBs and their cell voltages are comparable with carbon nanotubes.

Na-ion batteries based on the inorganic BN nanocluster anodes: DFT studies.

It has been recently indicated that the Li-ion batteries may be replaced by Na-ion batteries because of their low safety, high cost, and low-temperature performance, and lack of the Li mineral reserves. Here, using density functional theory calculations, we studied the potential application of B12N12 nanoclusters as anode in Na-ion batteries. Our calculations indicate that the adsorption energy of Na+ and Na are about -23.4 and -1.4kcal/mol, respectively, and the pristine BN cage to improve suffers from a low cell voltage (∼0.92V) as an anode in Na-ion batteries. We presented a strategy to increase the cell voltage and performance of Na-ion batteries. We showed that encapsulation of different halides (X=F-, Cl-, or Br-) into BN cage significantly increases the cell voltage. By increasing the atomic number of X, the Gibbs free energy change of cell becomes more negative and the cell voltage is increased up to 3.93V. The results are discussed based on the structural, energetic, frontier molecular orbital, charge transfer and electronic properties and compared with the performance of other nanostructured anodes.

Selective detection of cyanogen halides by BN nanocluster: a DFT study.

The electronic sensitivity and adsorption behavior toward cyanogen halides (X-CN; X = F, Cl, and Br) of a B12N12 nanocluster were investigated by means of density functional theory calculations. The X-head of these molecules was predicted to interact weakly with the BN cluster because of the positive σ-hole on the electronic potential surface of halogens. The X-CN molecules interact somewhat strongly with the boron atoms of the cluster via the N-head, which is accompanied by a large charge transfer from the X-CN to the cluster. The change in enthalpy upon the adsorption process (at room temperature and 1 atm) is about -19.2, -23.4, and -30.5 kJ mol-1 for X = F, Cl, and Br, respectively. The LUMO level of the BN cluster is largely stabilized after the adsorption process, and the HOMO-LUMO gap is significantly decreased. Thus, the electrical conductivity of the cluster is increased, and an electrical signal is generated that can help to detect these molecules. By increasing the atomic number of X, the signal will increase, which makes the sensor selective for cyanogen halides. Also, it was indicated that the B12N12 nanocluster benefits from a short recovery time as a sensor.

The interactional behaviors and photo-physical properties of azo-salicylaldehyde ligands in solvents media.

A quantitative study of solvent effects on photo-physical properties of some azo-salicylaldehyde Schiff Bases ligands, with various substituent and alkyl group, was carried out, at room temperature. The solvatochromic behavior of these substances and their solvent-solute interactions, both specific and non-specific, was analyzed using linear solvation energy relationship concept, suggested by Kamlet-Taft. The ground and excited state dipole moments of these substances and their molecular resonance structures were also evaluated via solvatochromic shift method.

The Possible Impact of Obesity on Androgen, Progesterone and Estrogen Receptors (ERα and ERß) Gene Expression in Breast Cancer Patients.

BACKGROUND: Obesity has been associated with increased mortality from hormone dependant cancers such as breast cancer which is the most prevalent cancer in women. The link between obesity and breast cancer can be attributed to excess estrogen produced through aromatization in adipose tissue. The role of steroid hormone receptors in breast cancer development is well studied but how obesity can affect the expression pattern of steroid hormones in patients with different grades of breast cancer was the aim of this study. METHODS: In this case-control study, 70 women with breast cancer participated with different grades of obesity (36 none obese, BMI < 25 kg/m(2) and 34 obese, BMI ≥ 25 kg/m(2)). The mean age of participants was 44.53 ± 1.79 yr (21-70 yr). The serum level of estrogen, progesterone and androgen determined by ELISA. Following quantitative expression of steroid hormone receptors mRNA in tumor tissues evaluated by Real-time PCR. Patients with previous history of radiotherapy or chemotherapy were excluded. SPSS 16 was used for data analysis and P < 0.05 considered statistically significant. RESULTS: The difference in ERα, ERß and PR mRNA level between normal and obese patients was significant (P < 0.001). In addition, the expression of AR mRNA was found to be higher than other steroid receptors. There was no significant relation between ERß gene expression in two groups (P = 0.68). We observed a significant relationship between ERα and AR mRNA with tumor stage and tumor grade, respectively (P = 0.023, P = 0.015). CONCLUSION: According to the obtained results, it is speculated that obesity could paly a significant role in estrogen receptors gene expression and also could affect progression and proliferation of breast cancer cells.